Week 4 - CR Response to Exercise Flashcards
ATP: what is it, what’s released during hydrolysis, how much do we store, + how long it sustains function
- An energy rich compound for biological work.
- Energy released during hydrolysis of ATP
- Store very little (250g)
- Sustains resting func. for 90s + 60s exercise.
ATP + H20 –>
ADP + Pi + H+ + 7kcaloffreeenergy/mol
ADP + H20 –>
AMP + Pi + H+ + 7kcaloffreeenergy/mol
ATP-CP Pathway
(Anaerobic)
-Fuel: stored phosphagens
-Speed of ATP mobilisation: very fast (4 mol ATP/min)
-Capacity: Very Limited
Phosphocreatine -> PO + Creatine + energy
ADP + P + Energy = ATP
Glycolysis
(Anaerobic)
-Fuel: Glycogen/glucose
-Speed of ATP mobilisation: Fast (2.5 mol ATP/min)
- Capacity: Limited
Glycogen -> pyruvic acid -> lactic acid (if O2 isn’t present)
Oxidative phosphorylation
(Aerobic)
- Fuel: Glycogen, glucose, fats, proteins
- Speed of mobilisation: Slow (1 mol ATP/min)
- Capacity: Unlimited
What energy pathway do we use at the beginning of activity + after that?
- The first 30sec. we use ATP-CP
- After: begin to use anaerobic glycolysis
- Lastly: Aerobic pathway-oxidative phosphorylation
- In reality : all 3 are active @ any time but to diff. degrees
Oxygen Consumption (VO2)
The amount of O2 taken up by the lungs
Cellular Oxygen Consumption (QO2)
The amount of oxygen taken up/consumed by the cells (i.e. skeletal muscle cells)
Maximal V02 (V02 max)
The maximal volume of oxygen that a body can take up and use.
What influences V02 max?
Age, intensity/volume of training, gender, mode of activity, environment(altitude/TM v trail), state of physical health, genetics (heart size/muscle type)
Fick Principle equation
VO2max = Q(max) x (Ca02 - CV02)max
Q= cardiac output
Difference on the contents of O2 in the arterial + mixed venous blood
(Ventilation) Ve=
Vt x f = 6 L/min
Fick’s law of diffusion
Vgas = (AxD(P1-P2)) / T A = surface area D= diffusion constant Partial pressure T = Thickness of alveoli capillary membrane
Affect of thickness of alveoli capillary membrane
- Thin makes it easier for diffusion
- Thicker in situations w/ fibrosis in membrane, could even happen w/ intense exercise due to pulm. oedema, inflamm., inhale of dust
VO2 + Ve during 5 min. of moderate intensity exercise
Both ventilation + Vo2 are steady at rest, increase during exercise, then goes down during recovery
Factors that influence breathing during exercise
- Respiratory center (situated in medulla/pons)
(1) gets inputs from the brain (relies on receptors)
(2) Sends info to phrenic nerve to make diaphragm/accessory muscles to contract
(increases VT + RR)
Peripheral chemoreceptors: what do they do + what can it identify
- Carotid bodies pick up low levels of O2 below 60mmHg + increased levels of CO2 or lactic acid
- Important in picking up hypoxemia (low oxygen) + metabolic acidosis
Central chemoreceptors: what is it + what can it identify
Brain; Neurons dotted around respiratory centre; important in picking up H20 ions due to an increase in C02
- Respiratory acidosis
What signals govern the Ve response to constant workload exercise?
I - Central command (brain warns body were exercising)
II - Short-term potentiation (stimulates neurons after resp. Centre is activated)
III - POSSIBLY Chemoreceptors in muscle, mechanoreceptors
- def not carotid bodies b/c O2 doesn’t drop enough, + CO2 doesn’t rise enough for it to be.
What signals govern the Ve response during incremental exercise?
- pH rises, CO2 + O2 decreases –> so pH is what’s really changing ventilation during incremental exercise
What increases ventilation at the end of a submax test (after ventilatory threshold)?
It is driven by carotid bodies (peripheral chemoreceptors) b/c build up of lactic acid, needs the carotid body to bring in the last bit of O2 to finish the aerobic work.
Role of the cardiorespiratory
- Deliver adequate oxygen + remove waste products from tissues.
- Transport nutrients
- Regulate temperature
Cardiac output (Q)
HR x SV (stroke volume)
